Multi-stage hydraulic jack



Nov. 15, 1960 1., ARNES MULTI-STAGE HYDRAULIC JACK Filed July 31. 1958INVENTOR. 1 74 A. 142916 BY MULTI-STAGE HYDRAULIC JACK Lyle L. Arnes,Racine, Wis assi gnor by mesne assignments, to Walker Manufacturingbompany, Racine, W1s., a corporation of Delaware Filed July 31, 1958,Ser. No. 752,246

9 Claims. (Cl. 12146) This invention relates to hydraulic jacks, andmore particularly to multi-stage jacks which have two or moretelescoping ram sections. A typical use of this jack is a substltute forthe unit 151 of US. Patent 2,837,222.

It is an object of the invention to provide an improved multi-stagehydraulic jack which minimizes fiuid leakage problems and may beinexpensively constructed using tubular elements which require a minimumamount of machining and may be quickly and easily assembled.

It is another object to provide an improved multi-stage hydraulic jackconstruction of the above nature which is sturdy and etficient inoperation and may be used with various types of pump arrangements and inany desired number of stages. Other objects, features and advantages ofthe present invention will become apparent from the following detaileddescription taken in conjunction with the accompanying drawing.

In the drawing:

Figure 1 is a cross-sectional view in elevation, with parts broken away,showing a multi-stage hydraulic jack constructed according to thepresent invention, the parts being shown in their collapsed position;and

Figure 2 is an enlarged fragmentary view of a lower portion of the jackshowing more clearly the fluidconducting passages.

In general terms, the illustrated embodiment of the invention comprisesa jack having a base, a cylinder mounted on the base, and a plurality ofram sections telescopically mounted within the cylinder. Two ramsections are shown in the illustrated embodiment, the first or outersection comprising a tubular member having a cylindrical guide sleevesecured to the lower end thereof by radially extending pins. The guidesleeve is slidably mounted within the cylinder while the first stage rampasses through a cap member secured to the outer end of the cylinder. Anannular space is provided between a major portion of the guide sleeveand the first ram, this space being open to the annular space whichexists between the outer ram and cylinder. Radial passages are formed inthe lower portion of the outer ram which connect with the space betweenthe outer ram and its guide sleeve. The inner ram section comprises acylindrical member the upper end of which is slidably mounted a glandnut carried by the upper end of the outer ram. A guide sleeve is fixedto the lower end of the inner ram and is slidably mounted in the outerram. The annular space between the inner and outer rams is connectedwith the pressure chamber by an axial passage formed in the lower end ofthe inner ram, the upper end of this passage being connected with aradial passage leading to the annular space between the two rams. Radialports are also formed in the lower portion of the inner guide sleeve,these ports being aligned with the radial ports in the outer ram whenthe inner ram is fully collapsed within the outer ram. An annular spaceformed between the lower end of the inner guide sleeve 2,960,072Patented Nov. 15, 1960 ice and the inner ram connects the radial portsin the inner guide sleeve with the pressure chamber.

Referring more particularly to the drawing, the jack is generallyindicated at 11 and comprises a base 12 having a lower ground-engagingsurface 13 and an upper boss 14. Although base 12 is only partiallyshown, it will be understood that it may support a pump arrangement (notshown) by means of which fluid under pressure enters pressure chamber 15of the base by means of passageways 16 and 17. A release valvearrangement (not shown) may also be carried by base 12, so that fluid isreleased from chamber 15 through passages 18 and 19. It should beunderstood that the particular pump arrangement and release valvemechanism in themselves do not form part of the present invention, andthat they could be incorporated as part of base 12 or mountedseparately.

A cylindrical reservoir casing 21 is threadably mounted in boss 14- andextends upwardly therefrom, a cap member 22 being secured to the upperend of casing 21. A threaded portion 23 is formed centrally of boss 14and extends downwardly into base :12, a cylinder 24 being threadablymounted in threaded portion 23 and extending upwardly therefrom. Theupper end of cylinder 24 is mounted in a downwardly extended threadedportion 25 of end cap 22. Seals 26 are provided between end cap 22 andcasing 21 and cylinder 24 respectively. These parts together form anannular reservoir chamber 27 which may be connected to the pump byappropriate passageways (not shown).

A guide bore 28 is centrally provided in end cap 22, and a tubular outerram section 29 is slidably mounted in this bore, a seal 31 beingprovided in the bore and engageable with the outer surface of ram 29.Ram 29 is of somewhat smaller diameter than cylinder 24 so that anannular space 32 is provided between these two members. The lower end ofram 29 carries a guide sleeve 33, this sleeve being of tubular shape andhaving its lower edge substantially coincident with the lower edge ofram 29. A radially extending pin 34 of rolled sheet metal having a gap40 passes through appropriate apertures in the lower ends of ram 29 andsleeve 33, securing these two members together for movement in unison.The lower portion of sleeve 33 has an inner diameter which isapproximately the same as the outer diameter of ram 29, but a majorportion of the inner diameter of sleeve 33 above pin 34 is relieved toprovide an annular space, indicated at 35, between sleeve 33 and ram 29,this space communicating with space 32. A plurality of radial ports 36are formed in the lower portion of ram 29 and serve to communicate thelower portion of space 35 with the inside of ram 29. An annular shoulder37 is formed on end cap 22 immediately above its connection withcylinder 24, this surface being engageable by the upper edge of sleeve33 when the jack is raised to limit the upper position of the outer ram.

An inner ram section 38 is disposed within ram section 29, rain 38comprising a cylindrical member of approximately the same length as ram29. A gland nut 39 is threadably mounted on the upper end of ram 29,this nut being engageable with the upper surface 41 of end cap 22 in thelower position of ram 29. Nut 39 carries a Wiper ring 42 and an annularseal 43, ram 38 extending through these elements and carrying a bushing44 at its upper end which may be connected to a load engaging element(not shown). An annular space 45 is provided between rams 29 and 38, andan air vent plug 46 is provided in nut 39 and is connected with space 45by a passage 47.

A guide sleeve 48 is secured to the lower end of ram 38, the lower edgeof this sleeve being approximately in the same plane as the lowersurface of ram 38, so

that these surfaces are engageable with pin 34 in the lower position ofram 38. Sleeve 48 is secured to ram 38 by a radially extending pin 49,this pin extending through appropriate apertures in the ram and guidesleeve. A plurality of radially extending apertures 51 are provided inthe lower portion of sleeve 48, these apertures being at approximatelythe same level as apertures 36 when both rams are telescoped. Acircumferential connecting channel or groove 52 is provided on the outersurface of sleeve 48 so that, with ram 38 collapsed within ram 29, ports36 and 51 will be in communication regardless 'of the relative angularpositions of the ram sections. An annular recess 53 is provided on theinner surface of guide sleeve 48, this recess connecting ports 51 withpressure chamber 15. An axial passage 54 is also provided in the lowerend of ram 38, this passage connecting chamber 15 with annular space 45by means of a radial passage 55 formed in rain 38 immediately abovesleeve 48. An annular shoulder 56 is provided on gland nut 39immediately above its connection with outer ram 29, this shoulderforming a stop for guide sleeve 48 in the upper position of ram 38.

In operation, assuming an initial condition in which the jack iscollapsed as shown in the figure and annular spaces 32 and 45 are filledwith fluid, application of fluid pressure to passage 16 will cause ramsections 29 and 38 to be raised. During this movement, fluid withinannular space 32 will flow through passage 35, ports 36 and ports 51 topassage 53, thus leaving space 32 as the latter diminishes in size andentering chamber 15. When sleeve 33 engages shoulder 37, movement of ramsection 29 will stop, and further application of fluid pressure tochamber 15 will cause ram section 38 to continue its upward movement.Fluid from annular space 45 will flow through passages 55 and 54 tochamber 15, this action continuing until the operator discontinues fluidflow from passage 16 to chamber 15, or when sleeve 48 engages shoulder56.

Upon release of pressure in chamber 15, rain section 38 will slidedownwardly within ram section 29, and as annular space 45 enlarges,fluid will flow from chamber 15 through passages 54 and 55 to chamber45. When ram section 38 engages pin 34, both ram sections will continuedownward movement together, with fluid flowing from chamber 15 throughpassages 53, 51, 36 and 35 to space 32. The main portion of fluidflowing from chamber 15 will of course exit through passages 18 and 19to reservoir chamber 27.

It will thus be seen that a novel and improved multistage hydraulic jackhas been provided which is of extremely inexpensive construction, and inwhich the passages necessary for proper fluid flow between the ramsections are formed in conjunction with tubular guide sleeves fixed tothe ram sections. Because of the unique construction, tolerance andsealing problems are greatly reduced, thus lessening fabricating costs.

While it will be apparent that the preferred embodiment of the inventionherein disclosed is well calculated to fulfill the objects above stated,it will be appreciated that the invention is susceptible tomodifications, variations and change without departing from the properscope or fair meaning of the subjoined claims.

What is claimed is:

1. In a multi-stage hydraulic jack, a base, a cylinder mounted on saidbase and having a cylinder chamber, an outer ram section of tubularshape mounted within said cylinder and spaced inwardly therefrom, atubular guide sleeve secured to the lower end of said outer ram sectionand slidably engaging said cylinder, an inner ram section disposedwithin said outer ram section and spaced inwardly therefrom, a tubularguide sleeve secured to the lower end of said inner ram section andslidably engaging said outer ram section, a passage between said outerram section and its guide sleeve connecting with the space between saidouter ram section and cylinder,

a first radial passage in the lower end of said outer ram sectionconnecting with said first-mentioned passage, a second radial passage insaid inner ram section guide sleeve adapted to be connected with saidfirst radial passage when the inner ram section is collapsed within theouter ram section, and a passage between said inner ram section and itsguide sleeve connected with the cylinder chamber.

2. In a multi-stage hydraulic jack, a cylinder having a chamber, anouter ram section disposed within said cylinder and spaced inwardlytherefrom, a first tubular guide sleeve fixed to the lower end of saidouter ram section and slidably engaging said cylinder, an inner ramsection disposed within said outer ram section and spaced inwardlytherefrom, a second tubular guide sleeve slidably engaging said outerram section, a radial pin securing said second guide sleeve to the lowerend of said inner ram section, a radial passage in said inner ramsection above said second guide sleeve leading from the space betweensaid inner and outer ram sections, and an axial passage in said innerram section extending past said pin and connecting said radial passagewith the cylinder chamber.

3. In a multi-stage hydraulic ram, a cylinder having a chamber, an outerram section disposed within said cylinder and spaced inwardly therefrom,a guide sleeve fixed to the lower end of said outer ram section andslidably engaging said cylinder, an inner ram section disposed withinsaid outer ram section and spaced inwardly therefrom, a guide sleevefixed to the lower end of said inner ram section and slidably engagingsaid outer rarn section, an annular passage between said outer ram section and its guide sleeve, a radial passage in said outer ram sectionleading inwardly from the lower end of said annular passage, a secondradial passage in the guide sleeve of said inner ram section, saidradial passages being in connecting relation when the inner ram sectionis in its collapsed position within said outer ram section, an annularpassage between the inner ram section and its guide sleeve connectingthe inner end of said second radial passage with the cylinder chamber,and a passage in said inner ram section connecting said cylinder chamberwith the space between said inner and outer ram sections.

4. In a multi-stage hydraulic ram, a cylinder, an outer ram sectiondisposed within said cylinder and spaced inwardly therefrom, a guidesleeve fixed to the lower end of said outer ram section and slidablyengaging said cylinder, an inner ram section disposed within said outerram section and spaced inwardly therefrom, the means for securing saidouter ram section to its guide sleeve comprising a radial pin, said pinserving to limit the collapsed position of said inner ram section withinthe outer ram section, a guide sleeve fixed to the lower end of saidinner ram section and slidably engaging said outer ram section, anannular passage between said outer ram section and its guide sleeve, aradial passage in said outer ram section leading inwardly from the lowerend of said annular passage, a second radial passage in the guide sleeveof said inner ram section, said radial passages being in connectingrelation when the inner ram section is in its collapsed position withinsaid outer ram section, an annular passage between the inner ram sectionand its guide sleeve connecting the inner end of said second radialpassage with the cylinder chamber, and a passage in said inner ramsection connecting said cylinder chamber with the space between saidinner and outer ram sections.

5. In a multi-stage hydraulic ram, a cylinder having a chamber, an outerram section disposed within said cylin der and spaced inwardlytherefrom, a guide sleeve fixed to the lower end of said outer ramsection and slidably engaging said cylinder, an annular passage formedbetween said outer ram section and guide sleeve connected with the spacebetween the outer ram section and cylinder, a radial passage in thelower end of said outer ram section connected with said annular passage,an inner ram section disposed within and spaced inwardly from said outerram section, a guide sleeve fixed to the lower end of said inner ramsection and slidably engaging said outer ram section, an annular groovein the outer surface of said inner ram section guide sleeve, said groovebeing aligned with said radial passage when the inner ram section iscollapsed within the outer ram section, a radial passage in said innerram section guide sleeve connected with said groove, and a passageformed between said inner ram section and its guide sleeve connectingsaid second radial passage with the cylinder chamber.

6. In a multi-stage hydraulic ram, a cylinder having a chamber, an outerram section disposed within said cylinder and spaced inwardly therefrom,a guide sleeve fixed to the lower end of said outer ram section andslidably engaging said cylinder, a radial pin connecting said outer ramsection and its guide sleeve, an annular passage between said outer ramsection and guide sleeve connected with the space between the outer ramsection and cylinder, a radial passage in the lower end of said outerram section connected with said annular passage, an inner ram sectiondisposed within and spaced inwardly from said outer ram section, a guidesleeve fixed to the lower end of said inner ram section and slidablyengaging said outer ram section, said radial pin between the outer ramsection and guide sleeve serving as a limit stop for the collapsedposition of said inner ram section, an annular groove in the outersurface of said inner rarn section guide sleeve, said groove beingaligned with said radial passage when the inner ram section is collapsedwithin the outer ram section, a second radial passage in said inner ramsection guide sleeve connected with said groove, an annular passagebetween said inner ram section and its guide sleeve connecting saidsecond radial passage with the cylinder chamber, a radial passage insaid inner ram section above its guide sleeve connected with the spacebetween said inner and outer ram sections, and an axial passage in saidinner ram section connecting said lastmentioned radial passage with saidcylinder chamber.

7. In a multi-stage hydraulic jack, a base, a cylinder mounted on saidbase and having a cylinder chamber, an outer ram section of tubularshape mounted within said cylinder and spaced inwardly therefrom atubular guide sleeve secured to the lower end of said outer ram sectionand having an outer surface slidably engaging said cylinder, an innerram section disposed within said outer ram section and spaced inwardlytherefrom, a second tubular guide sleeve secured to the lower end ofsaid inner ram section and having an outer surface slidably engaging theouter ram section, first passageway means connecting the space betweensaid outer ram section and cylinder from a level immediately above saidfirst-mentioned tubular guide sleeve with said cylinder chamber whensaid inner and outer ram sections are in their collapsed position withrespect to each other, and second passageway means connecting the spacebetween said inner and outer ram sections immediately above said secondtubular sleeve with said cylinder chamber.

8. In a multi-stage hydraulic jack, a base, a cylinder mounted on saidbase and having a cylinder chamber, an outer ram section of tubularshape mounted within said cylinder and spaced inwardly therefrom atubular guide sleeve secured to the lower end of said outer ram sectionand having an outer surface slidably engaging said cylinder, an innerram section disposed within said outer ram section and spaced inwardlytherefrom, means carried by the lower end of said inner ram section andslidably engaging said outer ram section, and passageway means leadingfrom the space between said outer ram section and cylinder at a levelimmediately above said guide sleeve to said cylinder chamber.

9. In a multi-stage hydraulic jack, a base, a cylinder mounted on saidbase and having a cylinder chamber, an outer ram section of tubularshape mounted within said cylinder and spaced inwardly therefrom, atubular guide sleeve secured to the lower end of said outer ram sectionand having an outer surface slidably engaging said cylinder, an innerram section disposed within said outer ram section and spaced inwardlytherefrom, means carried by the lower end of said inner ram section andslidably engaging said outer ram section, a passageway extending fromthe space between said outer ram section and cylinder immediately abovesaid sleeve downwardly between the sleeve and outer ram section, andpassageway means connecting said last-mentioned passageway with saidcylinder chamber.

References Cited in the file of this patent UNITED STATES PATENTS2,327,869 Carlson Aug. 24, 1943 2,438,285 Houldsworth Mar. 23, 19482,517,153 Wood Aug. 1, 1950 OTHER REFERENCES German Application No.D20723/Ia/60, Nov. 29, 1956.

